A debauched fellow, the largest of all birds. He sings more like a whore’s bird than a canary bird; said of one who has a strong manly voice.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Whittington’s College * Whore’s CurseNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes